Phase 2 of the Muddy River Flood Risk Management construction project in Boston and Brookline will be completed under the terms of a $36.5 million contract issued by the U.S. Army Corps of Engineers, New England District while the non-Federal sponsors for the project are the Commonwealth of Massachusetts, the City of Boston and the Town of Brookline, according to press release issued by the U.S. Army Corps of Engineers.
Work will be accomplished by Charter Contracting Company, LLC of Boston, and construction is scheduled to start on or about July 2020 and be completed in approximately 36 months. The contract was awarded on Feb. 26.
The overall project objective is to increase flood control through improvements to restrictive drainage culverts and by dredging accumulated sediment and removing invasive vegetation that is constricting flow. Positive ancillary benefits include improved water quality and enhanced aquatic/riparian habitat within Muddy River; bank stabilization; landscape restoration in keeping with the Frederick Law Olmsted’s famed “Emerald Necklace” parklands; and enhancing the overall recreational use of parklands.
Phase 1, completed in 2016, consisted of the major structural features of the flood damage reduction improvements: the installation of the two culverts (one under the Riverway and the other under Brookline Avenue); and daylighting of two sections (about 700 linear feet) of the Muddy River at the Former Sears Parking and at Upper Fens Pond. It also included bank restoration and planting emergent wetland plants and restoring riparian vegetation in upland areas by planting trees and shrubs.
Phase 2 is the final phase of work to complete the project, which addresses both upstream and downstream of Phase 1 work, and will consist of removal of river sediments for flow conveyance.
“The location of the work to be performed will be in and along the Muddy River from Leverett Pond to Boylston Street in Boston and Brookline,” Project Manager Jennifer Flanagan, of the Corps’ New England District, Programs and Project Management Division in Concord, Mass., stated in the press release. “The project scope of work consists of dredging 1 to 8 feet of sediment from the bottom of the river to construct the Flood Risk Management channel, stabilizing the material for transport, and trucking the material for disposal.”
Work will include excavating the river in the Back Bay Fens area of the Muddy River and excavating five stretches of the Riverway section of the Muddy River. It will include excavating the sandbar and island at Leverett Pond. Excavations may be performed mechanically in wet conditions or by the establishment of water diversion structures with excavation performed in dry conditions. Included as part of this work is additional flood protection at the Boston Fire Department Fire Control Center in the Back Bay Fens.
Work will include removal of phragmites in the Back Bay Fens and Riverway areas to achieve flood damage reduction; and restoring wetland vegetation in excavated areas by planting appropriate emergent wetland plants. It will include restoring riparian vegetation in upland areas where phragmitesare removed by planting trees and shrubs. It will include restoring vegetation and other landscape features disturbed at staging areas and within the limit of work; and installation of boulders and habitat logs for fish, turtles and amphibians
Additional work will include control of river flow; control of ground and surface waters; pedestrian and vehicular traffic control; pedestrian management; protection of historic structures and landscape features to remain; invasive species control and selective clearing of vegetation; and maintenance of all restored areas with the limit of work. Due to the urban setting of the project location, extensive management of pedestrian and vehicular traffic at construction access points and at each work area is required to minimize impacts to roadways and parkland system to ensure public safety. Preliminary preconstruction work, such as photographic and condition surveys and sediment sampling, will begin in mid-May in compliance with permit requirements and in support of the construction start in July 2020. The project will be managed by the Corps and supervised by a Corps’ Quality Assurance Representative to assure compliance with contract requirements.